This is a Continuation of Japanese Patent Application No. Hei. 11-261854, with a filing date of Sep. 16, 1999, the disclosure of which is incorporated into this application by reference.
1. Field of the Invention
The present invention relates to an apparatus for manufacturing lenses for vehicle lamps wherein lenses are molded integrally using at least two types of synthetic resins.
2. Description of the Related Art
In a conventional apparatus for manufacturing lenses for vehicle rear combination lamps wherein the lenses are molded integrally using at least two types of synthetic resins, e.g., a lens molded in two colors, a first cavity is defined by a first stationary mold and a common mold for injection of the first colored resin into the first cavity, and a second cavity is defined by a second stationary mold and the common mold for injection of the second colored resin into the second cavity.
To be specific, as shown in FIGS. 9 and 10, a first cavity 103 is defined by a common mold 101 and a first stationary mold 102, and a second cavity 105 is defined by the common mold 101 and a second stationary mold 104.
As shown in FIG. 11, a partition wall 108 having a width of, for instance, in the order of 5 mm is provided on the first stationary mold 102 in such a manner as to protrude therefrom so that when the common mold 101 and the first stationary mold 102 are assembled together, the first colored resin 107 is prevented from intruding into a portion 106 which constitutes a part of the second cavity 105 when the common mold 101 and the second stationary mold 104 are assembled together.
Following this, the second stationary mold 104 is assembled to the common mold 101 and the second colored resin 109 is injected into the second cavity 105 including the portion 106 with the first colored resin 107 being contained therein, whereby a lens 110 is produced.
When the common mold 101 and the first stationary mold 102 are assembled together so as to define the first cavity 103, since the distal end of the partition wall 108 abuts against a molding surface 111 of the common mold 101 which is a surface for molding the resin, several problems may occur. For instance, it has occurred that foreign particles are held between the partition wall 108 and the common mold 101, or that a contact mark of the partition wall 108 remains on the molding surface 111, or the molding surface 111 is damaged through repeatedly using the common mold 101 and the stationary mold 102.
Consequently, since the contact mark or the flaw is transferred to the lens 110, the appearance of the lens 110 is deteriorated. Alternatively, in a case where the location where the contact mark or the flaw is transferred is the surface of, e.g., a lens element, it has occurred that the lens is affected optically.
The present invention was made in view of the above problems, and an object of the present invention is to prevent a molding surface, of a vehicle lamp lens molding apparatus (wherein the lenses are molded integrally using at least two types of synthetic resin), from being marked after contacts with, or damaged by, a partition wall. The partition wall is necessary for preventing a first-molded resin from flowing into an area where another resin to be molded later is to be injected.
With a view to solving the problem, according to the invention, there is provided an apparatus for manufacturing lenses for vehicle lamps, wherein the lenses are formed from at least first and second types of synthetic resins by molding the first and second synthetic resins integrally with each other, the apparatus comprising a first mold comprising a common mold and a first stationary mold and defining a first cavity in which the first synthetic resin is injection molded, and a second mold comprising the common mold and a second stationary mold and defining a second cavity in which the first synthetic resin and the second synthetic resin are molded integrally with each other with the first synthetic resin being contained within the second cavity. Furthermore, a partition wall is provided on the first stationary mold, in such a manner as to protrude therefrom, for preventing the first synthetic resin from intruding into any place other than the first cavity when the first mold is closed, and wherein a distal end face of the partition wall is shaped such that the distal end face gradually tapers away from the common mold from a point on the distal end face closest to the first cavity to a point on the distal end face furthest from the first cavity.
Thus, there is no risk of a contact mark or a flaw being inflicted by the distal end face of the partition wall on the molding surface of the common mold.